This is a phase II, randomized, double blind study of idv with either dmp-266 or 1592u89, or with dmp-266 plus 1592u89 in subjects who have received zdv (or d4t) plus 3tc. A total of 450 subjects will be enrolled over a three month period. Lgible subjects will discontinue treatment with zdv (or d4t) and 3tc and be randomized with equal likelihood (stratified by cd4+ count and participatin in acting 320) to either L. Idv 1000 mg tid (q 8 hrs) + dmp-266 600 mg qd + 1592u89 placebo bid, 2. Idv 1000 mg tid (q8 hrs) + dmp-266 600 mg qd + 1592u89 300 mg bid or 3. Idv 800 mg tid (q 8 hrs) + dmp-266 placebo qd + 1592u89 300 mg bid. Subjects will be followed for the safety and tolrability of the drug combinations and the effect of the regimens on plasma HIV-RNA, cd4+ and cd8+ cells, quality of life, and clinical progression for 48 weeks beyond the enrollment of the last subject. Subjects with a confirmed detectable plasma HIV RNA (2 consecutive levels >/- 200 copies/mlll) at week 16 or thereafter will have the option to receive open-label idv, dmp-266, and 1592u89.